how does it work?
firewalls act as a "barrier to keep destructive forces away from your property". Firewalls can use three different ways to block out internet traffic.
On method is called packet filtering. This is where "small chunks of data" are filtered, if a packet is rejecting during this process it will be "discarded". Another method is a proxy service. This is when the firewall intercepts information and has a two way communication system with the "requesting system". The third method is stateful inspection. This type of firewall only compares "key parts of the packet to a database of trusted information", and discards all others. There are different types of filters that firewalls use. IP addresses, which are "32-bit numbers", can be read and blocked if they do not match a certain server. Another is the protocol that one uses. The protocol is a common way one service communicates with another. Protocols can include HTTP (hyper text transfer protocol), IP protocol, and FTP (file transfer protocol). "Specific words and phrases" can also be used to filter out certain, unwanted content. The text information is searched (sniffed) through and then discarded.
"How Firewalls Work ." HowStuffWorks? . N.p., n.d. Web. 20 Aug. 2010. <www.howstuffworks.com/firewall.htm>.
types of firewalls
network level firewalls these were the first genereation firewalls that worked at the basic network level and worked by inspecting packet headers and filtering traffic based oon the ip address of the source and the destination. Network level firewalls are fast and today they are generally buit into most routers. circuit-level firewalls Traffic is filtered based on specified session rules and may be restricted to recognized computers only. Circuit-level firewalls hide the network itself from the outside, which is useful for denying access to intruders. But they don't filter individual packets. application level firewalls application-level firewalls are sometimes called proxies and have been looking more deeply into the application data going through their filters. By considering the context of client requests and application responses, these firewalls attempt to enforce correct application behavior, block malicious activity and help organizations ensure the safety of sensitive information and systems. The downside to deep packet inspection is that the more closely a firewall examines network data flow, the longer it takes, and the heavier hit your network performance will sustain. stateful multi level firewalls s. They filter packets at the network level and they recognize and process application-level data, but since they don't employ proxies, they deliver reasonably good performance in spite of the deep packet analysis. On the downside, they are not cheap, and they can be difficult to configure and administer.
Why do organisations & individiuals use Firewalls
Organizations use more firewalls then most individuals do, they commonly have 2 or more firewalls. Individuals normally have 1 or 2. People use firewalls because it blocks other peoples access to your network. Without firewalls people would be able to access your computer.
How does it figure out what to block and what not to block
Firewalls come with a set list of things that they block, however it is possible to alter the firewall to allow different programs, or applications through the firewall.
how does it work?
firewalls act as a "barrier to keep destructive forces away from your property". Firewalls can use three different ways to block out internet traffic.
On method is called packet filtering. This is where "small chunks of data" are filtered, if a packet is rejecting during this process it will be "discarded". Another method is a proxy service. This is when the firewall intercepts information and has a two way communication system with the "requesting system". The third method is stateful inspection. This type of firewall only compares "key parts of the packet to a database of trusted information", and discards all others. There are different types of filters that firewalls use. IP addresses, which are "32-bit numbers", can be read and blocked if they do not match a certain server. Another is the protocol that one uses. The protocol is a common way one service communicates with another. Protocols can include HTTP (hyper text transfer protocol), IP protocol, and FTP (file transfer protocol). "Specific words and phrases" can also be used to filter out certain, unwanted content. The text information is searched (sniffed) through and then discarded.
"How Firewalls Work ." HowStuffWorks? . N.p., n.d. Web. 20 Aug. 2010. <www.howstuffworks.com/firewall.htm>.
types of firewalls
- network level firewalls these were the first genereation firewalls that worked at the basic network level and worked by inspecting packet headers and filtering traffic based oon the ip address of the source and the destination. Network level firewalls are fast and today they are generally buit into most routers. circuit-level firewalls Traffic is filtered based on specified session rules and may be restricted to recognized computers only. Circuit-level firewalls hide the network itself from the outside, which is useful for denying access to intruders. But they don't filter individual packets. application level firewalls application-level firewalls are sometimes called proxies and have been looking more deeply into the application data going through their filters. By considering the context of client requests and application responses, these firewalls attempt to enforce correct application behavior, block malicious activity and help organizations ensure the safety of sensitive information and systems. The downside to deep packet inspection is that the more closely a firewall examines network data flow, the longer it takes, and the heavier hit your network performance will sustain. stateful multi level firewalls s. They filter packets at the network level and they recognize and process application-level data, but since they don't employ proxies, they deliver reasonably good performance in spite of the deep packet analysis. On the downside, they are not cheap, and they can be difficult to configure and administer.
Why do organisations & individiuals use Firewalls- Organizations use more firewalls then most individuals do, they commonly have 2 or more firewalls. Individuals normally have 1 or 2. People use firewalls because it blocks other peoples access to your network. Without firewalls people would be able to access your computer.
How does it figure out what to block and what not to block